if you have 2spaces and 50 amp in your breaker box to spare and know some one who is apt in electrical you could add a 50watt breaker to your breaker box run conduit to a second breaker box in your grow room with 3 15amp breakers and then run some more conduit inside the room to boxes with outlets so you could get both lights and have a spare 15amp outlet to do what ya need with

depending how long ya talkin from growroom to breaker box your taking about
10-40bucks for the 50amp breaker (depend what kinda breaker box ya got)
12 for 3 15amp breakers
25 for the new breaker sub box for the grow room (make sure ya dont get the one with the expensive breakers)
9 for 3 electrical boxes with outlet covers
i dont know what conduit costs a foot copper prices are always changing
the prices for the components are whole sale ya might need to double them if its a homeboy doin the work from homedepot parts and always check local building and electrical codes